If you've used After Effects (this feature's probably in other editing programs, but I haven't used them so I'm not entirely sure), you're given the ability to smooth keyframes so movement seems a little more fluid and a little less linear.
This is already achievable in the Replay Mod manually, but being able to automate it would be really awesome. Perhaps being able to select multiple keyframes and pressing a hotkey to ease the movement would work. I suspect this would require not only a lot of code, but a lot of confusing math... a reason why it may not be achievable.
Here's a demonstration of what Easy Ease would look like vs. what it is now (this took a bit of time, haha):
Here's a path w/o Easy Ease.
Here's a rendition of what a path might look like w/ Easy Ease.
*It might not actually be that extreme of easing, I went a bit overboard with smoothing in the above gif.
Hopefully the above gfycats explain what I'm getting at, but if I failed to explain this feature, feel free to ask questions. I understand that this is a very unnecessary feature, just thought it would be yet another aspect that would help improve the Replay Mod, and the quality it produces!